Field of the Invention
This invention relates generally to wireline apparatus for sidewall coring in well bores drilled for production of petroleum products. More particularly, the present invention relates to rotary sidewall coring apparatus for acquiring multiple sidewall cores while operating in the downhole environment and for depositing the cores within a core receiving receptacle in such manner that individual cores may be separately classified so as to be related to formation depth when subsequent analysis is performed.
Discussion of Related Art
It is common geophysical practice to collect cores from oil and gas bore holes at known depth for analyzing the core materials in order to determine various characteristics of the subterranean earth formation.
Various sidewall coring apparatus has been developed and utilized for obtaining sidewall cores at selected depths. For the most part, however, these previous sidewall coring tools have the problem of easily stalling during coring activity because the coring bit thereof is typically operated by small high speed direct drive motors having only low torque capability. These types of coring tools typically have limitations that present a significant need which is effectively satisfied by the present invention.